It's a shame the people think Royo pieces will be worth a lot less if they aren't by Moser. It's like the quality doesn't matter as much as the name, and that's not right. Some Royo pieces are wonderful - the glass is creative and well-crafted, the enamel is nicely executed, the pieces reflect a unique Spanish glass tradition. And there are plenty of Moser pieces that aren't particularly high quality or noteworthy.
Every once in a while I write to a seller telling them they've made a wrong attribution. I think about half the time I get a reasonably polite note back. Many people don't want to be told they've got things wrong - go figure. I've almost stopped posting in the ebay Pottery Glass and Porcelain forum, I get so tired of people jumping to conclusions and holding on to them in the face of all evidence to the contrary (or no evidence). Sellers become blinded by the mighty dollar.
There's one ebay seller in particular that annoys me to no end by "guaranteeing" his/her wrong attributions.